Some folks have claimed that the disconnector is a "safety", preventing the an auto pistol from firing if the slide is not fully in battery. Some even tout it as a way to disarm an opponent by pushing on the muzzle of the gun so it can't fire.
"Disconnector" I assume is the modern common name of what I called the "battery safety." All the early Colt instruction manuals just refer to it as the "safety" on their parts diagrams. It is nice to know that one's pistol is designed to fire only when the breech is fully shut, and the design must be excellent, because I can't recall ever reading of a failure of this kind. But, I have never thought of such an arrangement as a safety, but rather just responsible design.
The Secret Service is reportedly trained to grasp the slide of a pistol and push it out of battery to keep the gun from firing. It will work, but I prefer to let someone else try it with a loaded gun.
Yeah, live-fire practice would be hairy.
A somewhat better case can be made for the inertia firing pin as a safety, since it prevents a hammer pistol from firing if a blow is struck to an uncocked hammer.
Again, I've never thought of this as a safety device, although I can see that a non-protruding firing pin does offer safety over a protruding counterpart. The rearward protrusion of my CZ 82/83s' firing pins are protected by a rebounding hammer safety.
In my mind, based on what was drummed into it when learning to shoot a half century ago, a safety is a device that prevents an inadvertent pull of the trigger from firing the gun, a device kept on, but never relied upon, until just prior to shooting when it is disengaged.
Passive safeties that don't play a conscious role in the shooting process don't seem to be safeties to me, but rather safe design elements. While it's nice to know how they work when they effect how one handles the gun, if it doesn't play a routine role in the process of firing, it isn't a safety. For example, knowing how the rebounding hammer on my CZ 82 works gives me the confidence to manually decock the gun safely with a live round in the chamber should I ever need to do so. However, I have never done so, as I carry it cocked and locked and, when pausing during a string of fire, simply activate the thumb safety lock to safe the pistol. Thus, while the rebounding hammer allows for safe decocking and prevents accidental firing should the gun fall and strike the hammer, it does not deserve the moniker "safety," but rather is a good feature of safe firearm design.
In my limited use of pistols with grip safeties the mechanism was entirely passive -- ie, disengaged and re-engaged with no thought on my part. As such, I would not regard it as a safety, but would welcome it as a safe design element of the gun. However, one gentlemen above mentioned, among other things, adjusting his grip to engage the grip safety while holstering. If that can be done with ease, I can see the value in doing so and that ability would elevate that safe design feature to the status of a safety in my opinion.